U.S. patent application number 10/942984 was filed with the patent office on 2006-03-23 for vapor pump power system.
Invention is credited to Donald R. Bedwell, Pat Romanelli, Robert J. Romanelli.
Application Number | 20060059912 10/942984 |
Document ID | / |
Family ID | 36072441 |
Filed Date | 2006-03-23 |
United States Patent
Application |
20060059912 |
Kind Code |
A1 |
Romanelli; Pat ; et
al. |
March 23, 2006 |
Vapor pump power system
Abstract
A power plant with at least two pressure vessels containing a
hydraulic fluid. A heat exchanging assembly is in heat transferring
association with the pressure vessels. The hydraulic conduit is
hydraulically connected with the pressure vessels. A power outlet
device is in hydraulic association with the conduit between the
vessels and is configured for outputing power from the flow of the
hydraulic fluid. A controlling mechanism is operably associated
with the heat exchanging assembly to cause the heat exchanging
assembly to alternately increase the pressure in one of the
pressure vessels compared to the other. Thus, hydraulic fluid is
caused to flow through the power outlet device alternately between
the pressure vessels to produce power from the power output
device.
Inventors: |
Romanelli; Pat; (Harrington
Park, NJ) ; Bedwell; Donald R.; (Columbia City,
IN) ; Romanelli; Robert J.; (Savannah, GA) |
Correspondence
Address: |
WINSTON & STRAWN LLP
1700 K STREET, N.W.
WASHINGTON
DC
20006
US
|
Family ID: |
36072441 |
Appl. No.: |
10/942984 |
Filed: |
September 17, 2004 |
Current U.S.
Class: |
60/645 ;
60/650 |
Current CPC
Class: |
F01K 27/005 20130101;
F01K 25/02 20130101 |
Class at
Publication: |
060/645 ;
060/650 |
International
Class: |
F01K 13/00 20060101
F01K013/00; F01K 25/02 20060101 F01K025/02; F02G 1/00 20060101
F02G001/00 |
Claims
1. A power plant, comprising: at least two pressure vessels
containing a hydraulic fluid; a heat exchanging assembly in heat
transferring association with the pressure vessels; a hydraulic
conduit hydraulically connecting the pressure vessels; a power
output device in hydraulic association with the conduit between the
vessels and configured for outputting power from the hydraulic flow
of the hydraulic fluid flowing through the conduit; and a
controlling mechanism operably associated with the heat exchanging
assembly for causing the heat exchanging assembly to alternately
produce increased pressure in one of the pressure vessels compared
to other such that the hydraulic fluid flows through the power
output device alternately between the pressure vessels to produce
the power.
2. The power plant of claim 1, further comprising an expandable
member in thermal association with the heat exchanging assembly for
expanding and contracting in response to alternating heat exchange
with the heat exchanging assembly, the expandable member being
operably associated with the hydraulic fluid in the pressure
vessels for biasing the hydraulic fluid alternately between the
pressure vessels through the conduit.
3. The power plant of claim 2, wherein the expandable member
comprises an expandable fluid disposed within at least one of the
pressure vessels in hydraulic association with the hydraulic
fluid.
4. The power plant of claim 3, wherein the expandable fluid is
substantially maintained within the power plant during cycles of
the hydraulic fluid flow.
5. The power plant of claim 3, wherein the expandable fluid
comprises a fluorocarbon.
6. The power plant of claim 3, wherein the expandable fluid
comprises a gas.
7. The power plant of claim 3, wherein the expandable fluid changes
between liquid and gaseous state during repeating cycles of
expansion and compression.
8. The power plant of claim 3, wherein: the heat exchanging
assembly is connected to hot and cold sources of a thermal
conducting fluid; and the controlling mechanism comprises at least
one temperature controlling valve to direct the thermal conducting
fluid alternately from the: hot source to heat the expandable
fluid, and cold source to cool the expandable fluid.
9. The power plant of claim 8, wherein the controlling mechanism
comprises: a controller operably associated with the temperature
controlling valve; and a vessel sensor in configured for sensing a
level of hydraulic fluid in at least one of the pressure vessels,
the controller being connected to the vessel sensor and configured
for operating the temperature controlling valve depending on the
level sensed by the vessel sensor.
10. The power plant of claim 9, wherein the vessel sensor is
associated with only one of the pressure vessels for sensing the
hydraulic fluid level therein.
11. The power plant of claim 9, wherein the controlling mechanism
comprises electric circuitry associated with the vessel sensor for
responding to the sensed hydraulic fluid level and controllingly
associated with the controlling valve.
12. The power plant of claim 2, wherein the expandable member is
configured to expand when heated and to contract when cooled.
13. The power plant of claim 1, wherein the conduit comprises:
outflow and inflow portions hydraulically connected between the
pressure vessels and the power output device; and flow directing
valves associated with the outflow and inflow portions for
directing the hydraulic fluid to flow from the pressure vessels to
the power output device only through the outflow portions, and from
the power output device to the pressure vessels only through the
inflow portions.
14. The power plant of claim 13, wherein the flow directing valves
comprise one-way flow valves.
15. The power plant of claim 13, further comprising an accumulator
hydraulically connected to the conduit at an accumulator location
between the output portions leading from the vessels for
substantially smoothing pressure and flow rate changes of the
hydraulic fluid flowing to the power output device.
16. The power plant of claim 13, wherein the conduit is configured
for flowing the hydraulic fluid in a closed figure eight circuit,
passing twice through the power output device before returning to
either pressure vessel.
17. The power plant of claim 16, wherein the conduit is configured
such that the hydraulic fluid in the closed circuit is directed
sequentially from a first of the pressure vessels, trough a first
of the outflow portions, through the power output device, through a
second of the inflow portions, to a second of the pressure vessels,
through a second of the outflow portions, through the power output
device, through a first of the inflow portions, and back to the
first pressure vessel.
18. The power plant of claim 1, further comprising an accumulator
hydraulically associated with the conduit for substantially
maintaining pressure and flow rate of the hydraulic fluid through
the power output device.
19. The power plant of claim 1, wherein the power output device
comprises a transducer for converting hydraulic power from the
hydraulic fluid flow.
20. The power plant of claim 19, wherein the power output device
comprises a hydraulic motor.
21. The power plant of claim 19, wherein the hydraulic motor
comprises a piston motor comprising at least one cylinder set
comprising a cylinder, a piston within the cylinder, and a crank
shaft driven by the piston to output the power.
22. The power plant of claim 20, further comprising: an intake
manifold connected to deliver the hydraulic fluid from the
hydraulic conduit to the cylinder to drive the piston; an exhaust
manifold connected to exhaust the hydraulic fluid from the cylinder
to the hydraulic conduit.
23. The power plant of claim 22, wherein the motor comprises at
least three cylinder sets.
24. A method of producing power in a power plant, comprising:
alternately and sequentially heating and cooling at least first and
second pressure vessels such that one of the vessels is heated
while the other is cooled to alternately increase a pressure in one
of the vessels with respect to the other for displacing a hydraulic
fluid reciprocally between the vessels through a hydraulic conduit;
and flowing the displaced hydraulic fluid in the conduit through a
power output device to cause the output device to output power.
25. The method of claim 24, wherein the pressure in the vessels is
varied by alternately heating and cooling an expandable gas within
the pressure vessels.
26. The method of claim 25, wherein the gas is substantially
maintained in the power plant throughout the alternating increase
and decrease of the pressures.
27. The method of claim 24, further comprising operating flow
directing valves associated for directing the hydraulic fluid in a
single direction through the power output device from the first to
the second pressure vessel and from the second to the first
pressure vessel.
Description
FIELD OF THE INVENTION
[0001] The present invention related to the production of power.
More particularly, the invention relates to producing power by
varying the temperature in pressure vessels to drive a hydraulic
fluid.
BACKGROUND OF THE INVENTION
[0002] The present day forms of creating power are generally
dependent upon the burning of fossil fuels to generate electric
power. In doing so, a serious environmental problem is created in
the form of air, water and land pollution. Also, in burning such
fuels to create kinetic energy, thermal efficiencies are relatively
low due to the formation of incomplete combustion products. This
results in exhaust pollution of these products, such as carbon
monoxide, carbon dioxide, nitrous oxides and particulates.
[0003] Certain attempts have been made to create power without
generating such pollutants. U.S. Pat. Nos. 4,086,772 and 4,170,116
disclose a continuous method and closed cycle system for converting
thermal energy into mechanical energy. This system comprises
vaporizing means, including an energy conversion tube having a
special nozzle section, for converting a liquid working fluid
stream to a vapor stream. This vapor stream operates a turbine
means wherein a portion of the energy of the vapor stream is
converted to mechanical shaft work. This system also includes means
for increasing the thermal and static energy content of the fluid
stream, this means typically being pump means. The vapor fraction
of that exits the turbine means passes through condensing means,
such as a diffuser, to regenerate the working liquid stream.
Finally, means are provided for recycling the condensed liquid
stream back to the vaporizing means. The working fluid may be
carbon dioxide, liquid nitrogen, or a fluorocarbon. Preferred
fluorocarbons are difluoromonochloromethane,
pentafluoromonochloroethane, difluorodichloromethane and mixtures
and azeotropes thereof.
[0004] U.S. Pat. Nos. 4,805,410 and 4,698,973 disclose closed loop
systems that recirculate a vaporizable working fluid between its
liquid and vapor states in a thermodynamic working cycle. In this
cycle, energy received from an external energy source is utilized
to vaporize the fluid to a high pressure in a boiler unit. The
resulting vapor is utilized in an energy utilizing device, such as
a slidable piston which causes rotation of a crank shaft coupled to
a flywheel to deliver mechanical output at a rotating shaft
connected thereto. Thereafter, the vapor is condensed into a
condensate at a relatively lower pressure in a condensing unit and
then is returned to the boiler unit for repeating of the
thermodynamic cycle. Also, the condensate flow between the
condensing unit and boiler unit is collected in one of two holding
tanks in selective pressure communication with the boiler unit.
Preferred working fluids include water, Freon or ammonia. Also,
thermal regeneration means may be included for providing
regenerative heating of the working fluid.
[0005] U.S. Pat. No. 5,551,237 discloses a method for producing
hydroelectric power in which sunlight is used to generate vapor in
a liquid. The vapor is then fed into tanks to push water out from
the tanks and through a Pelton wheel to generate power.
[0006] A power plant is needed that can more reliably and
efficiently produce power that can preferably allow a generally
continuous production.
SUMMARY OF THE INVENTION
[0007] The present invention is related to a power plant that has
at least two pressure vessels containing a hydraulic fluid. The
heat exchanging assembly is in heat transferring association with
the pressure vessels. A hydraulic conduit hydraulically connects
the pressure vessels, and a power output device is in hydraulic
association with the conduit between the vessels. The power output
device is configured for outputting power from the flow of the
hydraulic fluid through the conduit. A controlling mechanism is
operably associated with the heat exchanging assembly to cause the
heat exchanging assembly to alternately produce an increased
pressure in a first of the pressure vessels compared to a second of
the pressure vessels, and then increases in the second pressure
vessel unopened to the first, such that the hydraulic fluid flows
through the power output device alternatively between the pressure
vessels so that the power output device produces power.
[0008] In a preferred embodiment, an expandable member is provided
in thermal association with the heat exchanging assembly to expand
and contract in response to alternating heat exchange with the heat
exchanging assembly. The expandable member is preferably operably
associated with the hydraulic fluid in the pressure vessels to bias
the hydraulic fluid alternately between the pressure vessels
through the conduit and is in hydraulic association with the
hydraulic fluid. Expandable fluid can be substantially maintained
within the power plant, such that the cycling thereof is closed and
along a closed circuit. A preferred expandable fluid is a
fluorocarbon, and is preferably a gas. Additionally, the expandable
fluid can change between liquid and gaseous states during the
repeating cycles of expansion and contraction. The preferred
expandable member is configured to expand when heated and contract
when cooled.
[0009] Hot and cold sources of a thermal conducting fluid can be
provided in the heat exchanging assembly. Additionally, the
controlling mechanism can include at least one temperature
controlling valve to direct the thermal conducting fluid to the
pressure vessels alternately from the hot source to heat the
expandable fluid, and from the cold source to cool the expandable
fluid. A preferred controlling mechanism includes a controller that
is operably associated with the temperature controlling valve, and
a vessel sensor sensing association with at least one of the
pressure vessels. The vessel sensor is configured to sense the
level of hydraulic fluid within the vessel, and the controllers
connected to the vessel sensor and configured for operating the
temperature controlling valve depending on the hydraulic fluid
level that has been sensed. The vessel sensor is associated with
only one of the pressure vessels in a preferred embodiment, but can
alternatively be associated with other pressure vessels. The
controller can comprise electric circuitry associated with the
vessel sensor and for controlling the temperature controlling
valve.
[0010] The conduit preferably comprises outflow and inflow portions
that are hydraulically connected between the pressure vessels and
the power output device. Flow directing valves are associated with
the outflow and inflow portions to allow the hydraulic fluid to
flow only from the pressure vessels to the power output device in
the outflow portions, and from the power output device to the
pressure vessels in the inflow portions. The flow directing valves
can be one-way flow valves. In addition, an accumulator can be
hydraulically connected to the conduit upstream of the power output
device, such as between the outflow portions of the conduit, for
smoothing changes in pressure flow rate of the hydraulic fluid
flowing to and through the power output device. The accumulator can
be provided between two one-way flow valves that are configured to
allow flow only towards the accumulator from the pressure
vessels.
[0011] In embodiments in which inflow and outflow portions of the
conduit are provided, the hydraulic fluid can be configured to
hydraulically flow in a closed figure-eight circuit, passing twice
through the power output device before returning to a pressure
vessel from which it started. Although in the preferred embodiment
the outflow and inflow portions are directly connected to each
pressure vessel, in an alternative embodiment, these portions can
be connected to other portions of the conduit that lead directly to
the pressure vessels. The conduit can be configured so that the
hydraulic fluid in the closed circuit is directed sequentially from
a first of the pressure vessels, through a first of the outflow
portions, through the power output device, through a second of the
inflow portions, to a second of the pressure vessels, through a
second of the outflow portions, through the power output device,
through a first of the inflow portions, and back to the first
pressure vessel.
[0012] A preferred power output device comprises a transducer for
converting the hydraulic power from the hydraulic fluid flow. A
preferred transducer is a hydraulic motor or generator.
[0013] In a preferred method according to the invention, first and
second pressure vessel are alternatively and sequentially heated
and cooled. One vessel is heated while the other is cooled to
alternately increase the pressure of one of the vessels with
respect to the other. This displaces hydraulic fluid reciprocably
between the vessels through a hydraulic conduit. The hydraulic
fluid flows through the conduit and through a power output device
to produce the output power.
[0014] Preferably, the pressure in the vessels is varied by
alternately heating and cooling an expandable gas within the
pressure vessels. Additionally, the gas is preferably substantially
maintained within the power plant throughout the alternating
increase and decrease of pressures. Additionally, it is preferred
to operate flow directing valves to flow the hydraulic fluid in a
single direction to the power output device regardless of whether
the flow is from the first to the second pressure vessel or from
the second to the first pressure vessel. The present invention this
provides a simple power plant that can be worked with relatively
small temperature differences.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a schematic view of a power plant constructed
according to the present invention;
[0016] FIG. 2 is an enlarged cross-sectional view of a first
pressure vessel thereof, including a diagrammatic view of circuitry
to control heating and cooling of the pressure vessels;
[0017] FIG. 3 is a schematic view of another embodiment of a power
plant with an open heating and cooling circuit;
[0018] FIG. 4 is a diagram showing a preferred embodiment of a
power flow circuit according to the invention; and
[0019] FIG. 5 is a cross-sectional view of another embodiment of a
pressure vessel.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] Referring to FIG. 1, the preferred embodiment constructed
according to the invention includes first and second pressure
vessels 10,12 that are hydraulically connected via a hydraulic
conduit 14. In the preferred embodiment, two pressure vessels are
employed, although additional vessels can be used in alternative
embodiments. Additionally, each pressure vessel is preferably a
single vessel, but alternatively, several vessels can be linked as
to operate together as a single vessel.
[0021] Hydraulic fluid 16 is contained within the pressure vessels
10,12 and the conduit 14, which fluidly communicates the pressure
vessels 10,12 and allows the hydraulic fluid to flow from one
vessel to the other 12,10. The preferred conduit 14 includes vessel
outflow portions 18 connected to each pressure vessel 10,12 to
receive hydraulic fluid 16 flowing therefrom. The conduit 14 also
preferably includes vessel inflow portions 20 configured to direct
the hydraulic fluid 16 into each pressure vessel 10,12.
[0022] Between the vessel outflow portions 18, the conduit 14
includes a motor inflow portion 22 that directs the flowing
hydraulic fluid 16 from the vessel outflow portions 18 and delivers
it to a power output device, which in the preferred embodiment is a
motor 24 that includes a generator or alternator. A hydraulic or
pneumatic motor can be used. The power output device can
alternatively comprise another type of transducer for converting
hydraulic power from the hydraulic fluid flow into another form of
power, such as electrical power. The motor 24, which is thus in
hydraulic association with the conduit 14 between the pressure
vessels 10,12, is configured for producing power from the hydraulic
flow of the hydraulic fluid 16 that flows through the conduit 14.
The conduit 14 includes a motor outflow portion 26 hydraulically
connected to an outlet of the motor 24 that directs the flowing
hydraulic fluid 16 to the vessel inflow portions 20.
[0023] A user-controllable valve 28 can be provided, such as in the
motor inflow portion 22, as shown, or motor outflow portion 26 to
selectively stop the hydraulic fluid flow through the motor 24.
Flow directing valves 30,32,34 are preferably associated with the
vessel outflow and inflow portions 18,20 to direct the hydraulic
fluid 16 through the conduit 14. The flow directing valves 30,32,34
preferably cause the hydraulic fluid 16 to flow in a single
direction through the motor 24 and motor inflow and outflow
portions 22,26. The flow directing valves 30,32,34 also preferably
direct the hydraulic fluid 16 only out from the pressure vessels
10,12 and into the motor inflow portion 22 through the vessel
outflow portions 18, and to the pressure vessels 10,12 from the
motor outflow portion 26 through the vessel inflow portions 20.
[0024] This arrangement allows the use of a motor 24 or other power
output device that requires hydraulic flow therethrough in a single
direction. Other arrangements of flow directing valves 30,32,34 and
conduit 14 can be used for alternative types of power output
devices, such as devices that can employ flow in alternative
directions to produce power. The conduit 14 and the flow directing
valves 30,32,34 are preferably configured flowing the hydraulic
fluid 16 hydraulically in a closed figure-eight circuit. In the
preferred embodiment shown, this closed circuit passes the
hydraulic fluid 16 twice through the motor 24 before returning to
the same one of the pressure vessels 10,12.
[0025] Flow directing valves 30, which are associated with the
vessel outflow portions 18, are preferably one-way valves, such as
check valves or other suitable valves to allow flow in one
direction and block the flow in opposite direction. Other valves
used can be controlled electrically or in another manner to direct
the hydraulic flow. Flow directing valves 32,34 are preferably
electrically controlled, and are operated to cause the hydraulic
fluid 16 to flow from the motor outlet portion 26 to the pressure
vessel 10,12 other than the one from which the hydraulic fluid 16
was expelled in the current stage of operation. In the positions
shown in FIG. 1, valve 34 is open to allow the hydraulic fluid 16
to flow into pressure vessel 12, while valve 22 is closed, to
prevent flow through the vessel inflow portion 20 that is
associated with pressure vessel 10. In an alternative embodiment,
the valves 32,34 can be replaced with other types of suitable
valves, such as one-way valves, including check valves configured
to direct the flow along the desired path.
[0026] A hydraulic accumulator 36 can be hydraulically connected to
the conduit 14 to even the pressure and flow rate and smoothing
variations and spikes of the hydraulic fluid flow through the motor
24. Preferably, the accumulator 36 is connected to the conduit 14
downstream of flow directing valves 30 and upstream of the motor
24. A suitable location is between the vessel outflow portions
18.
[0027] The accumulator 36 preferably includes a spring 38 to
maintain a substantially consistent or constant pressure. The
spring 38 can be a gas spring, such as an air spring, and in the
preferred embodiment comprises compressed air at a pressure of
around 175 psi. Other suitable accumulator systems can
alternatively be used.
[0028] An expandable member is preferably operably associated with
the hydraulic fluid 16 in one or both the pressure vessels 10,12.
The expandable member preferably comprises a reversibly expandable
fluid 40 contained within one or both of the pressure vessels 10,12
in hydraulic association with the hydraulic fluid 16. When the
temperature of the expandable fluid 40 is changed, the expandable
fluid expands or contracts sufficiently and at a sufficient rate to
displace the hydraulic fluid 16 out from one of the pressure
vessels 10,12 to the other 12,10. Thus, one of the pressure vessels
10,12 is provided with a higher pressure than the other 12,10, to
bias the hydraulic fluid 16 between the pressure vessels 10,12 and
through the motor 24 to generate power.
[0029] A heat exchanging assembly is in heat transferring
association with the pressure vessels 10,12, and preferably with
the expandable fluid 40 therein. The heat exchanging assembly
preferably comprises a heat exchanger, such as a heat exchanger
coil 42,44 associated with, and preferably extending within, one or
both pressure vessels 10,12. Consequently, in the preferred
embodiment, the expandable fluid is in thermal association with the
heat exchanger coils 42,44, such that the heat exchanger coils
42,44 can alternately cause the expandable fluid 40 to expand and
contract by alternating the temperature of the expandable fluid 40.
In this manner, the internal pressures within the pressure vessels
10,12 are also varied. The expandable fluid 40 of the preferred
embodiment is configured to expand when heated and to contract when
cooled.
[0030] Although electric or other types of heat exchanging
assemblies can be used, the preferred heat exchanger coils 42,44
are connected to hot and cold sources 50,52 of a thermal conducting
fluid 45 via thermal conduits 46,48, such as water. The hot water
source 50 can be heated in manners known in the art, but preferably
employs a heat source that is readily available at the site at
which the power plant is to be employed. The hot water source 50
can be heated for example by sunlight, a furnace, or an outlet of
hot water from a factory, for example. If a source of hot water is
already available, the hot water itself can be used. The cold water
source 52 can also be cooled in a manner as known in the art, such
as by a refrigeration system, but a readily available source of
cold or cold water itself is preferably employed, such as water
from a local river or stream. If the requisite difference in
temperature can be obtained by simple heating the hot water source
without cooling the cold water source, or vice versa, such
arrangements can also be useable.
[0031] The thermal conduit 46 delivers the hot conducting fluid 45
to hot water valves 54,56, and the thermal conduit 48 delivers the
cold conducting fluid 45 to cold water valves 58,60. Valves 54,58
are connected to heat exchanger coil 42 of pressure vessel 10, and
valves 56,60 are connected to heat exchanger coil 44, to heat or
cool the expandable fluid 40 with in the respective pressure
vessels 10,12.
[0032] A controlling mechanism is preferably operably associated
with the heat exchanging assembly, and preferably the hot and cold
water valves 54,56,58,60 for controlling the operation thereof. The
controller of the embodiment shown is configured to open hot water
valve 54 and cold water valve 60 while closing cold water valve 58
and hot water valve 60 in a first stage of operation. Thus, hot
water is delivered through heat exchanger coil 42 to heat and
expand the expandable fluid 40 in the pressure vessel 10, and cold
water is delivered through heat exchanger coil 44 to cool and
contract the expandable fluid 40 in pressure vessel 12. In a second
stage of operation, the controller preferably closes hot water
valve 54 and cold water valve 60 and opens cold water valve 58 and
hot water valve 60. This causes cold water to be delivered through
heat exchanger coil 42 to cool and contract the expandable fluid 40
in the pressure vessel 10, and hot water is delivered through heat
exchanger coil 44 to heat and expand the expandable fluid 40 in
pressure vessel 12.
[0033] Pumps 62 can be provided for pumping the hot and/or cold
water through the heat exchanging assembly. Pumps 62 in the
embodiment shown are provided on the outlet side of the heat
exchanger coils 42,44, but in an alternative embodiment, the pumps
can be provided on the input side to the temperature controlling
valves 54,56,58,60.
[0034] Shutoff valves 64 are provided to shut off the flow of the
hot and/or cold water when desired. These shutoff valves 64 can be
solenoid operated valves that are controlled by the controller or
electrically by a separate switch.
[0035] In operation, the controller operates the temperature
controlling valves 54,56,58,60 in the first stage of operation to
heat the heat exchanger coil 42 to heat the expandable fluid 40 in
pressure vessel 10 and to cool heat exchanger coil 44 and
expandable fluid 40 in pressure vessel 12. These temperature
controlling valves 54,56,58,60 are preferably operated
substantially simultaneously. The expanding expandable fluid 40 in
pressure vessel 10 increases the pressure therein and forces out
hydraulic fluid 16 therefrom, which flows through the conduit 14
towards pressure vessel 12, in which the expandable fluid 40 is
contracted and in which the internal pressure has decreased. Check
valves 30 direct the hydraulic fluid 16 from pressure vessel 10
through the motor 24, which produces and outputs power, preferably
electric power, which can be used, or stored, for example, in a
battery. The controller causes valve 32 to close and valve 34 to
open, thus providing the path for the hydraulic fluid 16 to flow
into pressure vessel 12. FIG. 1 shows pressure vessel 10 full of
hydraulic fluid 16 with the expandable member 40 contracted, at the
beginning of the first stage. The level of hydraulic fluid 16 in
pressure vessel 12 is considerably lower than in pressure vessel
10, and there is a sufficient amount of space available therein to
be refilled with hydraulic fluid 16 after the first stage is
complete.
[0036] When the level of hydraulic fluid 16 in pressure vessel 10
reaches a predetermined low point, and pressure vessel 12 is full
of hydraulic fluid at the end of the first stage, the controller
causes the second stage of operation to begin. In the second stage,
the controller operates the temperature controlling valves
54,56,58, to heat the heat exchanger coil 44 to heat the expandable
fluid 40 in pressure vessel 12 and to cool heat exchanger coil 42
and expandable fluid 40 in pressure vessel 10. These temperature
controlling valves 54,56,58,60 again are preferably operated
substantially simultaneously. The expanding expandable fluid 40 in
pressure vessel 12 increases the pressure therein and forces out
hydraulic fluid 16 therefrom, which returns through the conduit 14
towards pressure vessel 10, in which the expandable fluid 40 is
contracted and in which the internal pressure has decreased. Check
valves 30 direct the hydraulic fluid 16 from pressure vessel 12
through the motor 24, which continues to produce and output power.
The controller causes valve 34 to close and valve 32 to open, thus
providing the return path for the hydraulic fluid 16 to flow into
pressure vessel 10. At the end of the second stage of operation,
pressure vessel 10 is again full of hydraulic fluid 16 with the
expandable member 40 contracted, and the level of hydraulic fluid
16 in pressure vessel 12 is again ready to receive hydraulic fluid
from pressure vessel 10 when the controller switches the operation
once again to the first stage. During this repeating cycle, in
which the hydraulic fluid 16 flows alternately between the pressure
vessels 10,12, the accumulator 38 smoothes power pulses by filling
as pressure increases in the conduit 14, and emptying when the
pressure decreases.
[0037] A vessel level sensor is preferably in sensing association
with at least one of the pressure vessels 10,12 for sensing the
level of hydraulic fluid 16 therein, sending a signal to the
controller to switch from between the first and second stages of
operation. A preferred vessel level sensor is shown in FIG. 2 and
includes high and low level sensors 66,68. The level sensors
include electrical switches that can be operated by floats or in
another manner to be sensitive to the hydraulic fluid level. In the
embodiment shown, the switches in the level sensors open and close
to control relays 70 in a single pole double throw circuit 72 and
in a double pole double through circuit 74. Electrical power is
preferably provided to the controller circuitry by power source 76,
which preferably comprises a battery charged by the motor 24. An
on/off switch 78 is provided to cut power from the system to stop
the power plant operation.
[0038] Referring to FIGS. 1 and 2, the controller operates such
that terminals T1 and T3 are powered during the first stage of
operation to open hot water valve 54, cold water valve 60, and
valve 32 with valves 34,56,58 closed. The double pole double throw
circuit 74 is then caused to remove power from terminals T1 and T3
and to power terminals T2 and T4 when the level of hydraulic fluid
16 reaches a predetermined low level 80 by operation of the low
level sensor 68 to initiate the second stage of operation.
Terminals T2 and T4 open cold water valve 58, hot water valve 56,
and valve 34, and valves 32,54,60 closed. When the hydraulic fluid
level reaches a predetermined high level 82, the controller returns
the first stage of operation, powering terminals T1 and T3.
[0039] An alternative controller employs a microprocessor and other
types of level sensors to signal the controller to change between
the stages of operation. Additionally, whereas in the preferred
embodiment the level sensors are only provided in one pressure
vessel 10, they can alternatively be provided in both pressure
vessels, with circuitry modified correspondingly.
[0040] In the preferred cycle, the expandable fluid 40 is
substantially maintained within the power plant, and most
preferably within the pressure vessels. The preferred cycle is thus
closed with respect to the flow of the hydraulic fluid 16 and
expandable fluid 40. The expandable fluid 40 preferably comprises a
fluorocarbon or other refrigerant. Also, the preferred expandable
fluid 40 comprises a gas, and in some embodiments can change
between a liquid and gaseous state during repeating cycles of its
expansion and compression.
[0041] Although the invention is illustrated with the use of an
expandable fluid, any type of expandable member can be used. For
example, a solid such as ice can expand as it warms to provide a
pressure. Generally, any fluid (i.e., gas or liquid) that expands
or contracts with heating or cooling can be used. It is also
desirable that the expandable member generate relatively high
pressures at a relatively low temperatures. Advantageously, the
expandable fluid comprises a fluorocarbon or fluorocarbon mixture
that (a) generates a high pressure of at least 100 to 400 psi or
more at a pressure generation temperature that is below the boiling
point of water, (b) has a boiling point which is below the freezing
point of water, and (c) has a critical temperature which is above
that of the pressure generation temperature. Preferably, the
expandable fluid comprises a fluorocarbon mixture that (a)
generates a high pressure of at least 500 psi at a pressure
generation temperature that is below 190.degree. F., (b) has a
boiling point which is at least 10 degrees F. below the freezing
point of water, and (c) has a critical temperature which is above
150.degree. F.
[0042] Any one of a wide variety of expandable fluids can be
utilized in this invention. Advantageously, these fluids generate
relatively high pressures at temperatures that are well below the
boiling point of water, and generally below 190.degree. F. for the
specific fluids disclosed herein. These fluids also have boiling
temperatures that are significantly below the freezing point of
water. Pressures of at least about 100 to as high as about 500 to
700 psi can be provided at a temperature in the range of about 120
to 180.degree. F., with the most preferred fluids having pressure
generating temperatures of between about 140 and 160.degree. F.
These high pressures are advantageous for efficiently operating
turbines or related equipment for generating power or torque.
[0043] The most advantageous fluids are fluorocarbons, and while a
single fluorocarbon may be used alone, it is preferred to instead
use various mixtures and most preferably to utilize azeotropic
mixtures. Suitable fluorocarbons for use as mediums include
difluoropentafluoroethane, trifluoromethane, pentafluoroethane,
tetrafluoroethane, and trifluoroethane. Certain mixtures may
contain small amounts of other gases such as hydrocarbons or
halogenated hydrocarbons provided that the overall properties of
the mixture meet the above-stated property requirements.
[0044] The most preferred fluorocarbons and fluorocarbon mixtures
include HFC-125, Blends 404A, 407C, and HP-80, Azeotrope 502, and
Azeotropic mixtures AZ-20 and AZ-50, all of which are available
from Allied Signal Chemicals, Morristown, N.J. AZ-20 is disclosed
in U.S. Pat. No. 4,978,467, while AZ-50 is disclosed in U.S. Pat.
No. 5,211,867. Other useful fluorocarbon mixtures are disclosed in
U.S. Pat. No. 5,403,504. Each of these three patents is expressly
incorporated herein by reference to the extent needed to understand
these compounds.
[0045] The most preferred expandable fluid 40 is AZ 20, with which
relatively small temperature differences between the hot and cold
states of the heat exchange coils 42,44 and expandable fluid 40 can
produce large changes in pressure and volume of the fluid 40. The
maximum difference in temperature of the expandable fluid 40 is
preferably less than about 100.degree. F., and more preferably less
than about 75.degree. F. One embodiment using AZ 20 uses about a
50.degree. F. maximum difference between the heated and the cooled
expandable fluid 40 in the pressure vessels 10,12, with the heated
expandable fluid 40 being at about 90.degree. F. to about
130.degree. F., for example at about 100.degree. F., and the cooled
expandable fluid 40 being at around 35.degree. F. to about
80.degree. F., for example about 50.degree. F. A preferred minimum
temperature difference is about 10.degree. F., and more preferably
about 20.degree. F. The expandable fluid 40 in both pressure
vessels 10,12 are preferably heated and cooled between
approximately the same temperatures and pressures.
[0046] A preferred pressure difference between the heated and
cooled expandable fluid 40 in the pressure vessels 10,12 driving
the hydraulic fluid 40 through the motor is less than about 500
psi, and more preferably less than about 350 psi, and preferably
more than about 50 psi. In a preferred embodiment, one pressure
vessel is pressurized up to about 320 psi, while the other has a
pressure of down to about 140 psi. The temperatures and pressures
can be selected based on desired power output, materials used, and
resources available.
[0047] In another embodiment, shown in FIG. 3, the heating and
cooling thermal conducting fluid 45, such as the hot and cold water
in thermal conduits 46,48, is expelled from the system in an open
flow circuit. This can be beneficial when water can easily be
emptied into a nearby area, and a hot and cold water source are
naturally or otherwise already available to operate the power
plant.
[0048] Referring to FIG. 4, an embodiment of the motor 24 is a
piston motor 84 with one or more cylinders. The piston motor 84
that is shown has three cylinders 92 in a radial arrangement,
although other arrangements and number of cylinders can be used,
such as in-line, V, or horizontally opposed.
[0049] Valves 86 are operated by the controller to alternately
direct the hydraulic fluid through the outflow portions 18 of the
conduits 14 to an intake manifold 88, which distributes the
hydraulic fluid through intake conduits 90 that lead to each
cylinder 92. Exhaust conduits 96 deliver hydraulic fluid that exits
the cylinders 92 to an exhaust manifold, which is connected with
the inflow portions 20 of conduit 14. Valves 98 are operated in
association with valves 68 by the controller to direct the
hydraulic fluid to the appropriate pressure vessel 10,12, depending
on the present stage of operation.
[0050] Pistons 100 are disposed within the cylinders 92 and are
connected to a crank shaft 102 by piston rods 104, with the crank
shaft 102 preferably connected to a generator or other power
mechanism. Intake and exhaust valves 94,95 are preferably operated
depending on the position of each piston 100 within the cylinders
to deliver and exhaust the hydraulic fluid 16 from the cylinders
92. The valves 94,95 can be operated mechanically, electrically,
electronically, or by other suitable methods known in the art.
[0051] During operation of each cylinder 92, the intake valve 94
opens to admit hydraulic fluid from the high pressure intake
manifold 88 in to the cylinder 92 to drive the piston 100 down and
rotate the crank shaft 102 during a power stroke. In an exhaust
stroke, the piston 100 rises, preferably driven by the crankshaft
102, to expel the hydraulic fluid 16 from the cylinder 92 to the
low pressure exhaust manifold 98.
[0052] A preferred embodiment employs at least three cylinders 92
so that no initial motion needs to be imparted on the motor 94 to
start it moving in the desired direction. In the arrangement shown,
for example, with the cylinders 92 placed equidistantly around the
crankshaft 102, the pistons are preferably about 60.degree. out of
phase, so at least one is in the power stroke, which will cause the
initial turning of the shaft 102 to be in the desired rotational
direction.
[0053] Another embodiment of a pressure vessel 10 or 12 is shown in
FIG. 5, which is compartmentalized into a plurality of subvessels.
A first subvessel 104 surrounds an expandable fluid chamber 106
that contains the expandable fluid 40, and which is preferably
substantially rigid to hold its shape during the cycles of
operation. Hot and cold heat conducting fluid 45 are alternately
flowed through inlet and drain tubes 118 and through a jacket
region 108 surrounding the expandable fluid chamber 106 to alter
the temperature of the expandable fluid 40 in chamber 106. A
conduit 110 allows the expandable fluid 40 to reciprocate between
chamber 106 and an expandable chamber 112, for example formed as a
bellows. A hydraulic fluid subvessel 114 contains the hydraulic
fluid 16 and s preferably substantially rigid to hold its shape
through the pressure cycles of the hydraulic 16 fluid therein. The
volume of the expandable chamber 112 changes cyclically in response
to the temperature change of the expandable fluid 40, thus pumping
the hydraulic fluid 16 out of, and allowing the hydraulic fluid 16
back into, subvessel 116 during the operation.
[0054] While illustrative embodiments of the invention are
disclosed herein, it will be appreciated that numerous
modifications and other embodiments may be devised by those skilled
in the art. For instance, the hydraulic fluid can be any suitable
fluid, including water, and is preferably substantially
incompressible. Alternatively, the hydraulic fluid can be
compressible, and can be a gas, such as air, and in one embodiment
is substantially the same fluid as the expandable member. Also, the
heat exchanging mechanism can include a separate heater, such as an
electrical resistance heater, which may be directly associated with
the pressure vessels. Therefore, it will be understood that the
appended claims are intended to cover all such modifications and
embodiments that come within the spirit and scope of the present
invention.
* * * * *